. The street railway review . he pole, and are held so tightly and so near the armature that the protecting end canvas is often cut through. Thistype of the field may have done good service years ago, but ithas such drawbacks that it had to give way to the iron-cladfields. (Fig. 14). Fields which expose the poles to the arm-ature, but have almost no stray magnetism, as the so-calledindifferent core portion, is made use of to surround the arm-ature, poles and coils, to protect these parts in a similar man-ner, but still more effectively than the pans, which every-where made the same impression
. The street railway review . he pole, and are held so tightly and so near the armature that the protecting end canvas is often cut through. Thistype of the field may have done good service years ago, but ithas such drawbacks that it had to give way to the iron-cladfields. (Fig. 14). Fields which expose the poles to the arm-ature, but have almost no stray magnetism, as the so-calledindifferent core portion, is made use of to surround the arm-ature, poles and coils, to protect these parts in a similar man-ner, but still more effectively than the pans, which every-where made the same impression as awkward and cumber-some parts which ought to be dispensed with. Next in turn,as a weak construction, is the armature of those days whencarried over to perform service in these days of heavy wish to refer to the smooth armature of the drum or ringtype. (Figs. 15 and 16). In either case the wire is woundon the smooth surface, and surrounds the iron types of armature construction may be well for gen-. only to realize the improvement, but they make demands forquicker service, disregarding the number of people a motorwould have to transport. The increased travel made it anecessity to construct motors, not only more powerful, butconstructed on more sound mechanical principles. Referringnow to Fig. 7, we have here the well known two , which has spoiled so many watches. We find thelower coil and one pole within four or six inches from theground, and it has been necessary to protect them by pans,which are often left off. Any iron, nails or wires lying inthe street is picked up by the attraction of the magnet, andworks its way up to the pole, aided by the constant jarringand vibration caused by the roughness of joints or picking up of iron pieces is often the cause of scrapingthe insulation and of connecting the outside layer of the wind-ing to the field pole, grounding the field and causing a severebucking. (See Fig. 13). In following t
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Keywords: ., book, bookcentury1800, bookdecade1890, booksubjectstreetrailroads
